Method of manufacturing flatirons and the like



Sept. 8, 1936. Y J. w. MYERS 2,053,405

METHOD 0F MANUFACTURING FLATI'RONS AND THE LIKE Filed Aprii 2, 1935- 2sheets-sheer 1 sept.s,193s. A JQ w. MYERS Y 2,053,405

METHOD 0F MANUFACTURING FLATIRoNs AND THE LIKE Filed April 2, Y19155 2Sheets-Sheet 2 enemies secr. a 'ieee STAT ME'rnon or MANUrac'rUarNoJoseph W. Myers, Philadelphia, lila., enf menne assignments, to a iinc., Bhilstlelplnla, Pa., a o

sylyania Application April 2, Iiig Serial This invention relates to themanufacture of electrical appliances, such as nat-irons, and particularly to processes of manufacturing the heating units of suchappliances. The invention is s directed speciiically to that class ofelectrical appliances in. which the electrical element is positionedwithin a cavity or recess of the appliance. The invention is intendedprimarily for applicaz tion to electric fiat-irons, in which the heatingelement is disposed within a cavity or recess in the sole plate of theiron, but the invention is not thus limited and is applicable to otherappliances and, in fact, has utility in any instance where the desiredpurpose may be served. For the. purpose of disclosure, the inventionwill be described with particular reference to an electric at=iron- Itis now common practice in the manufacture ci an electric flat-iron toimbed the heating element in the form of a coil in refractory insulatingmaterial within a cavity or recess oi the sole plate above referred to.Heretoiore, the method I, of manufacture has involved the followingsteps. Some of the refractory insulating cement mois tened with water isrst placed directly in the cavity or recess of the sole plate orcasting, after which the heating element is positioned in proper placeupon the cement. The heating element is then covered by placing more ofthe insulating material over it and the previously1 deposited material.Pressure is then applied to the insulating material to compact it inplace. .The material is then allowed to dry slowly to eliminate themoisture, and finally the unit is burned or tired to set the cement andremove smoke and fumes from the organic material `usually present in it.In some instances, intermediate drying operations are employed,depending upon the consistency of the insulating material or mixture andthe shop procedure oi the manufacturer.

This prior process has certain serious objections, the chief oi whichare the multiplicity of steps or operations necessary and the extensivehandlirig required. In an article such as an electric fiat-iron, whichis plated and bued to a mirror iinish, itis desirable to reduce to, aminimum `the handling of the plated sole plate in which the heating unitis to be imbedded. The imbeddlng material which is commonly employed isusually extremely abrasive, such material usually having a largepercentage of fused aluminum oxide, granulated zirconium silicate,ground quartz or the like. If the material comes into contact with theplated .sole plate, there is likely to be produced on the sole plateundesirable scratches which, even though slight, may permanently injurethe plate from. the standpoint o appearance and later sale oi thecompleted article. is apt to happen, and. frequently does happen, theuse oi the prior method or process aioye de scribed. f3

The present invention has for its principal che ject, therefore, theprovision of a novel process which eliminates the objections of theprior proc ess and which produces a superior product,

A more specific object of the invention is to pro l@ vide a processwhich involves a minimum number of steps and minimum handling oi theplated soie plate of the article, and which substantially eliminates thepossibility oi injury to the plated surfaces of the iron.

The invention may be clearly understood from the following descriptionwith reference to thc accompanying drawings, in which Fig. l illustratesthe heating element in its initial condition;

Fig. 2 is a perspective view of the preformed heating unit formed by theprocess;

Fig. 3 is a similar view oi another preformed part;

Fig. i is a perspective View of the heating unit 25 at a later stage inthe process;

Fig. S is a perspective view of the sole plate of the flat-iron;

Fig. 6 is a perspective view oi? the cover plate sections;

Fig. 7 is a perspective view ci the sole plate with the preformed unitapplied thereto;

Fig. 8 illustrates the iinal step of the process; and

Fig. 9 is a cross-sectional view of the completed product.

In accordance with the preferred form of the process, the heatingelement is iirst formed as illustrated in Fig. i, and the preformedheating unit shown in Fig. 2 is then formed by molding refractoryinsulating material around the heating element. This may be done by anyof the methods well known in the ceramic molding art. Preferably, thefiati-iron and the heating unit therefor is of the form disclosed andclaimed in my copending application, Serial No. 716,874, filed March 22,1934 and the sole plate of the iron is of the form illustrated in Fig.5. For this reason, the preformed unit in its initial stage preferablytakes the form ci' a stick or bar, as shown in Fig. 2, with spacednotches i which may be readily iormedtduring the preiorming operationand the purpose oi' which will be exn plained presently. The heatingelement, whose terminals are shown et a, is entirely surround 2li tricalcharacteristics, temperature of omration .of the unit, etc. As the sizeof the refractory the dimensions of the cavity or recess of the sole'plate so that it may nt easily therein.

In accordance with the invention, a refractory insulating material isused which will now or extrude in the dry state under applied pressure.

under pressure.

I iind that the addition of talc to the usual mixw ture of. clay andrefractory grains assists this flow. The talc content may be as large as199% of the weight of the grain used. However, a good mixture forpracticing my invention consists of 50% fused alumina grain of about 15usize, 25% talc, and 25% refractory clay. f These propor-= tionsconstitute a little more than enough talc and clay to ll the interspacesbetween the grains. so that the grain and nller will extrude and dow Theproportions ygiven are not the only proportions which may be used, andmay vary considerably, depending upon. the elec= grains also determinesthe mobility thereof, this is a factor to be considered. A suitableorganic binder such as is used in making foundry cores may be added tothe mix in sumcient quantity to render the preform coherent, and topermit of rough handling.

Following the formation of the preformed unit shown in Fig. 2, using amobile mixture or material as above described, the unit is allowed todry by letting it stand for a i'ew days. The unit is then baked at atempeature of 500 'to 600 F. to remove the organic material usuallypresent and to remove also the smoke and fumes caused thereby. Thepreformed unit is then re to be placed in the channel or recess of thesole plate. In this state, the unit is sumciently hard to permit ofrough handling and to Substantially eliminate the presence of any looseabrasive particles, but it is brittle and capable of being cbled orcrushed by relatively high pressure.

Referring to Figs.- i and 5, the preioed unit is bent at the notchesabove mentioned and formed to the shape shown in Fig. d to adapt it forinsertion in the channel or recess l of the sole plate E5, the brittleinsulating material break ing at the points of bend. The sharp bendingof the unit at the notches l and the consequent breaking of theinsulating material exposes the heating element at the corners t, or atleast ren ders the insulating material thin at those points, and thevo'ids formed at these corners when the unit is placed in the channel ilare lled by means of the preformed triangular pellets or inserts l, suchas illustrated in Fig. 3. These rfif in serts may be formed of the sameinsulating ma terial and in the same manner as the unit itself. The soleplate with the preformed heating unit and inserts l applied thereto isshown in Fig. L After the shaped preformed unit is placed in the recessor channel of the sole plate, the cover plate or cap illustrated in Fig.d is placed over the unit in the channel. The cover plate may comprisetwo sections 8 as illustrated, shaped in conformity with they channeland formed of sheet metal. The edges of the cover plate sections arebent downwardly so as to engage the side walls of the channel when thesections are expanded therein. ff

The sole plate with the assembled heating unit is then placed in ahydraulic press or like device, as illustrated in Fig. 8, and pressureis applied to the cover plate or cap sufclent to crush or crumble therefractory material and consolidate aoeasoe it in intate contact withthe walls of the chan nel or recess. This pressure may be in theneighborhood of 8 tons to the square inch of ere posed cap surface. Verylittle, if any, displacement oi the heating coil results, so that theneces sary clearance between the channel wall and the coil ismaintained. The sole plate'structure is now completed and ready forapplication oi the usual cover and handle, after which the nat-iron iscompleted and ready for use. ItV is unnecessary to lire or balie theheating unit after it has been pressed into the sole plate or casting.

The completed sole plate structure is illustrated in Fig. 9. Thedownwardly-turned edges of the cover plate or cap are expanded outwardagainst the side walls of the channel when the pressure is applied asabove described, thus loclr=- -ing the cover plate in place. The coverplate or cap prevents the escape of any of the material oi which theunit is formed around the edges ci the pressing punch or after the unitis in service. It also serves to carry the heat which arises from theheating coil back into the sole plate or casting, particularly by virtueof the contact of its edges or anges with the side walls of the channel.As previously mentioned, this 'structure forms the subject of acopending application.

It will be seen that this process reduces to a minim the handling of thesole plate ln the presence oi the refractory material. IThe saidmaterial is brought into association with the sole plate only when thesolid preformed heating unit is placed in the channel and pressed to itsunal condition. At no time is there any loose moist cement or abrasivematerial in the vicinity of the sole plate.

The process is simple and involves a minimum number of steps oroperations and at the same vtime it results in an improved article. Theiincommodating the same need 'not take the specic forms illustrated, theinvention contemplating broadly the formation of the preformed unit andits later application to the sole plate. More-vi over, theprccess may bemodied as to its de= I claim:

l. In the manufacture of electric appliances, such as nat-drone, themethod which comprises initially preforming an electrical heating unitby molding about a current conductor a body of mobile refractoryinsulating material shaped to rit in a cavity or recess of the appliancethus forming a self-supporting unit comprising only the insulatingmaterial and the embedded conductor, placing the preformed unit in thesaid cavity or recess with said insulating material contacting the wallsof said cavity, and subjecting the unit to pressure sumcient to crushand consolidate the unit in its cavity.

' 2. ln the manufacture of electric appliances, such as nat-irons, themethod which comprises initially prefog an electrical heating unit bymolding about a current conductor a. body of mobile refractoryinsulating'material shaped to t in a cavity or recess of the appliancethus forming a self-supporting unit comprising only the insulatingmaterial and the embedded conductor, placing the preformed unit in thesaid cavity or recess with said insulating material contacting the wallsof said cavity, covering the unit with a sheet metal cap to seal thesaid cavity or recess, and applying pressure to said cap suillcient tocrush and consolidate the unit in the cavity and to lock the captherein.

3. In the manufacture of electric appliances. such as fiat-irons, themethod which comprises initially preforming an electrical heating unitby molding completely about a current conductor a body of mobilerefractory insulating material shaped to fit in a cavity or recess ofthe appliance thus forming a self-supporting unit comprising only theinsulating material and the embedded conductor, placing the preformedunit in the said cavityor recess with said insulating materialcontacting nie wus of said. cavity, covering the unit with a sheet metalcap having turned-down edges to seal the said cavity or recess, andapplying lpressure to said cap sumcient to crush and consolidate theunit in the cavity and to lock the cap therein.

4. In the manufacture of electric appliances, such as flat-irons, themethod which comprises initially preforming an electrical heating unitby molding completely about a current conductor a body of mobilerefractory insulating talc-containing material shaped to ilt in a cavityor recess of the appliance thus forming a self-supporting unitcomprising only the insulating material and the embedded conductor,placing the preformed unit in the said cavity or recess with saidinsulating material contacting the Walls of said cavity, and subjectingthe unit to pressure sufilcient to crush and consolidate the unit in itscavity.

5. In the manufacture of electric appliances, such as flat-irons, themethod which comprises initially preforming an electrical heating unitby molding completely about a current conductor a body of mobilerefractory insulating material shaped to nt in a cavity or recess of theappliance thus forming a self-supporting unit comprising only theinsulating material and the embedded conductor, said material containingan extrudable filler capable of flowing under pressure when dry, placingthe preformed unit in the .said cavity or recess with said insulatingmaterial contacting the Walls of .said cavity, and subjecting the unitto pressure suiuclent to crush and consolidate tile unit in its cavity.

6. In the manufacture of electric appliances, such as flat-irons, themethod which comprises initially preformed an. electrical heating unitby molding completely about a current conductor a body of mobilerefractory insulating material shaped to iit in a cavity or recess ofthe appliance thus forming a selfnsupporting unit comprising l itscavity.

only the insulating material and the embedded conductor, drying thepreformed unit, placing the preformed unit in the said cavity or recesswith said insulating material contacting the walls of said cavity, andsubjecting the unit to pressure suillcient to crush and consolidate theunit in its cavity.

7. In the manufacture of electric appliances, such as fiat-irons, themethod which comprises initially preforming an electrical heating unitby molding completely about a current conductor a body of mobilerefractory insulating material shaped to fit in a cavity or recess ofthe appliance thus forming a self-supporting unit comprising only theinsulating material and the embedded conductor, baking the preformedunit, placing the preformed unit in the said cavity or recess with saidinsulating material contacting the walls of said cavity, and subjectingthe unit to pressure sufficient to crush and consolidate the unit in itscavity.

8. In the manufacture of electric appliances, such as fiat-irons, themethod which comprises initially preforming an electrical heating unitby molding completely about a current conductor a body of mobilerefractory insulating material shaped to fit in a cavity or recess ofthe appliance thus forming a self-supporting unit comprising only theinsulating material and the embedded conductor, drying the preformedunit, baking the unit, placing the preformed unit in the said cavity orrecess with said insulating material contacting the walls of saidcavity, and subjecting the unit to pressure sumclent to crush andconsolidate the unit in its cavity.

9. In the manufacture of electric appliances, such as flat-irons, themethod which comprises preforming a stick-like electrical unit bymolding about a current conductor a body of mobile refractory insulatingmaterial dimensioned to flt in a cavity or recess of the appliance andprovided with spaced notches, bending said unit at the said notches toshape it in conformity with said cavity or recess, placing the shapedunit in the said cavity or recess together with inserts at the bentnotched portions of the unit, and subjecting the unit to pressuresumcient to crush and consolidate the unit in its cavity.

lit-In the manufacture of electric appliances, such as flat-irons, themethod which comprises preforming a stick-'like electrical unit bymolding about a current conductor a body of mobile re 'Jessen w. MYERS.

